In participants with a diagnosis of open angle glaucoma (OAG) or ocular hypertension (OHT), the primary objective is to demonstrate that the mean IOP reduction after 3 months of treatment with BOL-303259-X once daily (QD) is non-inferior to timolol maleate 0.5% twice daily (BID). The secondary objective is to demonstrate the superiority of BOL-303259-X QD to timolol maleate 0.5% BID. This assessment will be performed if the non-inferiority of BOL-303259-X QD to timolol maleate 0.5% BID is determined. An open label safety phase will be conducted at the end of Visit 6 (3 months) where all participants will receive BOL-303259-X QD for an additional 9 months.